"Jen's had it," says a close friend. "As if it's not enough that she's getting grief over the Brangelina engagement, with everyone pointing out that she's still childless and husband-less, now she's still got this hangover from Justin's past haunting her!"

Getting Justin away from Heidi, who lives in New York City, was a huge reason for Jen's dramatic and abrupt decision to relocate back to L.A., sources say. But apparently, the West Coast wasn't far enough.

Pals claim Jen hates that Justin is still in touch with Heidi and last week decided she'd had enough. "She told him he had to decide between her or Heidi — and it caused a huge bust-up between them," the pal says.

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